1. Field of the Invention
The present invention relates to novel compositions of matter and methods of using said compositions. More particularly, it relates to compositions of matters useful as mold release and parting agents, for protecting and lubricating the surfaces of molds and other article-forming parts, especially such as are useful in the manufacture, forming and handling of glass articles or the like at high temperatures.
2. Description of the Prior Art
In glass manufacturing, a glob of molten glass is formed by a blank mold into a parison having a finished portion corresponding to the neck portion of the desired glass article. It is a requirement that the molding surface of the blank mold not become abraded or pitted so that the molten glass will readily flow over the molding surface of the mold, take the shape thereof, and then separate therefrom. Protection and lubrication are therefore required. It is known that the glob of molten glass delivered to a glass forming machine has an average surface temperature of about 1600.degree. to 1700.degree. F. Thereafter, during the final process of shaping and forming, the molten glass has cooled to a temperature between about 1250.degree. and 1350.degree. F. As can be appreciated, this cooling process renders the glass less plastic and often creates a dragging effect upon the molding surface of the equipment.
Several practices have been followed in the past for the protection and lubrication of such molds used in forming glass articles. Typically, it has been the practice to apply to such molds various compositions or dopes containing a graphite compound or the like suspended in a carrier. Often hydrocarbons of some type, such as kerosene have been used. Generally these compositions are applied by spraying, painting or swabbing during the forming operations so as to provide lubrication of the interacting mold sections and to prevent sticking of the molten glass to the mold surfaces. It will be appreciated that there are some drawbacks in such compositions containing hydrocarbons as well as their method of application. Since the glass molds are at an elevated temperature, the hydrocarbon materials are quickly driven off into the atmosphere. Aside from the obnoxious odors, the vaporized materials create considerable volumes of smoke which reduce visibility, and produce upon condensation serious fire hazards which often times become progressively worse as the accumulation increases. Further, the application of the composition to various moving parts of the machine in actual production must be regularly repeated a number of times on a regular basis which could result in injury to the operators. Needless to say, these disadvantages have required that the industry employ other solutions to circumvent these undesirable conditions. Further discussion of the long-existing problems with such compositions and efforts to avoid these problems can be found in U.S. Pat. Nos. 3,141,752; 3,480,422; 3,508,893; 3,523,016 and 3,623,856.
A number of aqueous systems have been employed with various degrees of success. Various mixtures and compositions employing inorganic binders have been used for coating molds for their protection in which water is used as a carrier. Illustrative of these aqueous formulations containing an inorganic binder is U.S. Pat. No. 1,568,234 which discloses a coating composition for protecting molds, the composition consisting of an inert refractory material such as clay, lampblack and a soluble silicate.